Industrialized countries rely upon transportation systems such as over-the-road trucks, trains, airplanes and boats for distribution and transportation of both large objects and bulky commodities. It is important to the safety of the transportation vehicle, whether it be a truck, car, boat or train, and to the safety of the cargo that the transported cargo is stabilized while being transported. If cargo shifts during transport, the cargo can be damaged and the inside of the cargo container can be damaged. Further, if the cargo is not sufficiently stabilized to avoid shifting, the cargo can unbalance the vehicle and create a dangerous situation. For example, if a vehicle is loaded so that the cargo is distributed evenly between the wheel base of the cargo container and the cargo slips forward while the vehicle is traveling downhill, the shifting cargo can cause the vehicle to lose control and often results in flipping the vehicle over.
To avoid cargo shifting, cargos are packed as carefully as possible in the container to eliminate any open spaces within the cargo to minimize the possibility of the cargo shifting. In many circumstances, however, the weight of the cargo or the nature of the cargo and the size of the cargo container in which it is to be packed is such that open spaces within the cargo container cannot be eliminated. This is especially true where the cargo is heavy, as many vehicles are restricted by weight as to the amount of cargo that they can carry. In order to fill the open regions that remain in the cargo container, it is desirable to provide some type of restraining device or spacing device between the cargo and either the front wall or the back wall or the side wall of the cargo container. These devices have to be constructed to withstand the shifting forces typically encountered during transport. Likewise, they must be relatively lightweight and preferably capable of retro-fitting into any type of cargo container and not permanently mounted within the cargo container. It is also preferred the space filling devices can collapse or be dismantled into a smaller, more easily manageable size so that they can be removed and stored.
One example of an existing space filling device which is in commercial use for truck trailers is a metal and wood system that is welded into the inside of the trailer. This is used for trucks which haul cans of beverages such as soda and beer. Since the weight of the canned beverage is such that, under some governmental regulations, large semi-trucks cannot be loaded completely. Furthermore, since the beer must be loaded between wheels for balance, void spaces are left between the cargo and both the front and back portions of the trailer. To accommodate this packaging of cargo in the middle of the trailer, metal rails are welded onto the sides of the front and the back of the trailer of the truck. A metal bar has one end inserted in one side rail and a second end inserted in the second side rail so that the bar extends across the cargo container parallel to the end walls. Likewise, a second metal bar is inserted in the back portion of the truck. The bars have large pieces of plywood attached to them. The bars are slid within the rails so that the plywood is secured against the cargo. The bars are then locked into place on the side rails. Although this device does restrain the cargo, this type of a cargo retaining device has some disadvantages. It is costly to install. It is permanent as it requires that the side rails be welded into the side walls of the truck. Many commercial trucking companies do not wish to have permanent side rails welded onto their trucks. Plus, this cargo retaining system is quite heavy as it requires metal side rails, metal bars and plywood for restraining the cargo. The weight added by the space filling device reduces the cargo weight which can be hauled.
Although the above space filling device is suitable for use in retaining cargo for shipment, it is generally more complex to use and more permanent than is desirable. Accordingly, there remains a need for an improved space filling device that is lightweight and inexpensive, and that can be retro-fitted into a cargo container without the necessity of permanently affixing rails on the inside of the cargo container.